[openssl-users] EC_KEY_check_key

[Jakob Bohm]

On 02/11/2018 08:50, Thulasi Goriparthi wrote:
> Hi,
>
> I am going through the checks done by EC_KEY_check_key method. I see
> the following checks in order.
>
> 1. Is point at infinity? - reject.
> 2. Is point not on curve? reject.
> 3. Is point not in the primary subgroup? reject.
> 4. If priv key(scalar) available, then check if scalar * G != point.
> If so, reject.
>
> If priv key is available and we do step 4, isn't step 3 redundant? Can
> we change this to something like this?
>
> if (priv key)
>      step 4
> else
>     step 3

For such tests, it's always better safe than sorry.


Enjoy

Jakob
-- 
Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
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